Initial commit of sparse Rips, based on Rips_complex.

git-svn-id: svn+ssh://scm.gforge.inria.fr/svnroot/gudhi/branches/sparserips-glisse@3137 636b058d-ea47-450e-bf9e-a15bfbe3eedb

Former-commit-id: f0550a0a24a25e8d9ab16535eb4364e8dc4228e6

1 files changed, 145 insertions, 0 deletions

diff --git a/src/Rips_complex/utilities/sparse_rips_persistence.cpp b/src/Rips_complex/utilities/sparse_rips_persistence.cpp
new file mode 100644
index 00000000..12b3b099
--- /dev/null
+++ b/src/Rips_complex/utilities/sparse_rips_persistence.cpp
@@ -0,0 +1,145 @@
+/*    This file is part of the Gudhi Library. The Gudhi library 
+ *    (Geometric Understanding in Higher Dimensions) is a generic C++ 
+ *    library for computational topology.
+ *
+ *    Author(s): Marc Glisse, Clément Maria
+ *
+ *    Copyright (C) 2014  INRIA
+ *
+ *    This program is free software: you can redistribute it and/or modify
+ *    it under the terms of the GNU General Public License as published by
+ *    the Free Software Foundation, either version 3 of the License, or
+ *    (at your option) any later version.
+ *
+ *    This program is distributed in the hope that it will be useful,
+ *    but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *    GNU General Public License for more details.
+ *
+ *    You should have received a copy of the GNU General Public License
+ *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <gudhi/Sparse_rips_complex.h>
+#include <gudhi/distance_functions.h>
+#include <gudhi/Simplex_tree.h>
+#include <gudhi/Persistent_cohomology.h>
+#include <gudhi/Points_off_io.h>
+
+#include <boost/program_options.hpp>
+
+#include <string>
+#include <vector>
+
+// Types definition
+using Simplex_tree = Gudhi::Simplex_tree<Gudhi::Simplex_tree_options_fast_persistence>;
+using Filtration_value = Simplex_tree::Filtration_value;
+using Sparse_rips = Gudhi::rips_complex::Sparse_rips_complex<Filtration_value>;
+using Field_Zp = Gudhi::persistent_cohomology::Field_Zp;
+using Persistent_cohomology = Gudhi::persistent_cohomology::Persistent_cohomology<Simplex_tree, Field_Zp >;
+using Point = std::vector<double>;
+using Points_off_reader = Gudhi::Points_off_reader<Point>;
+
+void program_options(int argc, char * argv[]
+                     , std::string & off_file_points
+                     , std::string & filediag
+                     , double & epsilon
+                     , int & dim_max
+                     , int & p
+                     , Filtration_value & min_persistence);
+
+int main(int argc, char * argv[]) {
+  std::string off_file_points;
+  std::string filediag;
+  double epsilon;
+  int dim_max;
+  int p;
+  Filtration_value min_persistence;
+
+  program_options(argc, argv, off_file_points, filediag, epsilon, dim_max, p, min_persistence);
+
+  Points_off_reader off_reader(off_file_points);
+  Sparse_rips sparse_rips(off_reader.get_point_cloud(), Gudhi::Euclidean_distance(), epsilon);
+
+  // Construct the Rips complex in a Simplex Tree
+  Simplex_tree simplex_tree;
+
+  sparse_rips.create_complex(simplex_tree, dim_max);
+  std::cout << "The complex contains " << simplex_tree.num_simplices() << " simplices \n";
+  std::cout << "   and has dimension " << simplex_tree.dimension() << " \n";
+
+  // Sort the simplices in the order of the filtration
+  simplex_tree.initialize_filtration();
+
+  // Compute the persistence diagram of the complex
+  Persistent_cohomology pcoh(simplex_tree);
+  // initializes the coefficient field for homology
+  pcoh.init_coefficients(p);
+
+  pcoh.compute_persistent_cohomology(min_persistence);
+
+  // Output the diagram in filediag
+  if (filediag.empty()) {
+    pcoh.output_diagram();
+  } else {
+    std::ofstream out(filediag);
+    pcoh.output_diagram(out);
+    out.close();
+  }
+
+  return 0;
+}
+
+void program_options(int argc, char * argv[]
+                     , std::string & off_file_points
+                     , std::string & filediag
+                     , double & epsilon
+                     , int & dim_max
+                     , int & p
+                     , Filtration_value & min_persistence) {
+  namespace po = boost::program_options;
+  po::options_description hidden("Hidden options");
+  hidden.add_options()
+      ("input-file", po::value<std::string>(&off_file_points),
+       "Name of an OFF file containing a point set.\n");
+
+  po::options_description visible("Allowed options", 100);
+  visible.add_options()
+      ("help,h", "produce help message")
+      ("output-file,o", po::value<std::string>(&filediag)->default_value(std::string()),
+       "Name of file in which the persistence diagram is written. Default print in std::cout")
+      ("approximation,e", po::value<double>(&epsilon)->default_value(.5),
+       "Epsilon, where the sparse Rips complex is a (1+epsilon)-approximation of the Rips complex.")
+      ("cpx-dimension,d", po::value<int>(&dim_max)->default_value(1),
+       "Maximal dimension of the Rips complex we want to compute.")
+      ("field-charac,p", po::value<int>(&p)->default_value(11),
+       "Characteristic p of the coefficient field Z/pZ for computing homology.")
+      ("min-persistence,m", po::value<Filtration_value>(&min_persistence),
+       "Minimal lifetime of homology feature to be recorded. Default is 0. Enter a negative value to see zero length intervals");
+
+  po::positional_options_description pos;
+  pos.add("input-file", 1);
+
+  po::options_description all;
+  all.add(visible).add(hidden);
+
+  po::variables_map vm;
+  po::store(po::command_line_parser(argc, argv).
+            options(all).positional(pos).run(), vm);
+  po::notify(vm);
+
+  if (vm.count("help") || !vm.count("input-file")) {
+    std::cout << std::endl;
+    std::cout << "Compute the persistent homology with coefficient field Z/pZ \n";
+    std::cout << "of a sparse (1+epsilon)-approximation of the Rips complex \ndefined on a set of input points.\n \n";
+    std::cout << "The output diagram contains one bar per line, written with the convention: \n";
+    std::cout << "   p   dim b d \n";
+    std::cout << "where dim is the dimension of the homological feature,\n";
+    std::cout << "b and d are respectively the birth and death of the feature and \n";
+    std::cout << "p is the characteristic of the field Z/pZ used for homology coefficients." << std::endl << std::endl;
+
+    std::cout << "Usage: " << argv[0] << " [options] input-file" << std::endl << std::endl;
+    std::cout << visible << std::endl;
+    std::abort();
+  }
+}